Bis-alkylene pyrophosphate-urea reaction products as slow-release fertilizers

ABSTRACT

Bis-alkylene pyrophosphate-urea reaction products are employed as the active ingredient in slow-release nitrogenous-phosphorus fertilizers to provide a continuous supply of nutrients for improving the growth of plants.

United States Patent Goring et a1.

BIS-ALKYLENE PYROPHOSPHATE-UREA REACTION PRODUCTS AS SLOW-RELEASEFERTILIZERS Inventors: Cleve A. l. Goring; Henry H. Scott,

both of Walnut Creek Calif.

The Dow Chemical Company. Midland, Mich.

Filed: Jan. 2, 1973 Appl. No.: 320.676

Related U.S. Application Data 133375. April 12.

Assignees Division of Ser. No. 1971,

abandoned.

U.S. Cl. 71/29; 71/64 SC Int. Cl CflSb 15/00 Field of Search 260/920,933 938, 968;

References Cited UNITED STATES PATENTS 9/1941) Barcroft 71/27 1 1 May13, 1975 Primary E.\'aminerChar1es N. Hart Attorney, Agent. or Firm-S.Preston Jones 1 1 ABSTRACT Bis-a1ky1ene pyrophosphate-urea reactionproducts are employed as the active ingredient in s1ow-re1easenitrogenous-phosphorus fertilizers to provide a continuous supply ofnutrients for improving the growth of plants.

1 Claim, No Drawings BlS-ALKYLENE PYROPHOSPHATE-UREA REACTION PRODUCTSAS SLOW-RELEASE FERTILIZERS CROSS-REFERENCE TO RELATED APPLICATIONS Thisis a division of application Ser. No. 133,375 filed Apr. l2, 1971, andnow abandoned.

BACKGROUND OF THE INVENTION With the advent of modern agriculturalmethods and the increased use of chemical fertilizers, it has becomeapparent that the development of means to allow the regulated dispersalof plant nutrients is of great importance. Areas of particular interestfor such products are in gardening, planting of forest seedlings,nurseries and in turf management. Additionally, a chemical fertilizerwhich could be applied in a single application and have a regulateddispersal would require less labor and would last for long periods oftime which would be of excellent utility and great value.

Various means have been proposed to effect the slow-release of plantnutrients such as, for example, alteration of the physical and/orchemical structure of the nutrients themselves. Examples of thisapproach include the use of urea-formaldehyde condensation products andvarious chelated materials as fertilizers.

Other methods for prolonging the release of fertilizers provide forcoating of the fertilizer pellet, Such methods are taught in US. Pat.Nos. 3,l50,955; 3,192,031; 3,259,482; 3,502,458; 2,806,773, 2,019,824and others. Some have resorted to encasing fertilizers in cartridges orshells such as those taught in US. Pat. Nos. 3,060,012; 2,931,l40;2,032,608 and 3,057,713.

However, numerous disadvantages have been encountered in the use of mostof these approaches. Such disadvantages include the high cost of thematerials, the inability to provide complete coatings and the incompleteor poorly timed release of the nutrient materials.

SUMMARY OF THE lNVENTlON The present invention is directed to aslow-release nitrogenous-phosphorus fertilizer composition having as theactive component the condensation product obtained by condensing ureawith a bis-alkylene pyrophosphate and to a method of use therefor.

The urea-bis-alkylene pyrophosphate condensation products employed inthe practice of the present invention are known products and are thesubject of U.S. Pat. No. 3,507,936; the disclosure of said patent whichincludes the method of preparation of the condensation products isincorporated herein by reference thereto.

The products which are employed as the active component in the presentinvention are prepared by condensing from about 1 to about 5 molecularequivalents of urea with a bis-alkylene pyrophosphate at an ele' vatedtemperature. The preferred condensation product contains about 3molecular equivalents of urea to l of bis-alkylene pyrophosphate.

The pyrophosphate has the formula wherein R represents an alkylene orsubstituted alkylene radical of 2-8 carbon atoms in which the carbonatoms of attachment to the phosphate group are either vicinal or areseparated by a single carbon atom. The alkylene groups may bear inertsubstituents, such as cy cloalkyl or phenyl. Such compounds are knownand can be made, for instance, by the method set forth in US. Pat. No.3,l59,59l.

The preferred pyrophosphates are of vicinal alkylene phosphates whereineach alkylene group contains 2-4 carbon atoms, these being the mostreactive and producing the condensation products having the highestcontent of phosphorus and nitrogen. Representative preferred alkyleneand substituted alkylene radicals include, for example, ethylene, l,2-or l,3-propylene. l,2-, 2,3- or 1,3- butylene, 1.2-, 2,3-, l,3-, 2,4- or3,4- octylene, phenyiethylene, l-phenyl-2,3-butylene and cyclohexylene.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS In order that the presentinvention may be more fully understood, the following examples are givenprimarily by way of illustration and should not be construed aslimitations upon the overall scope of the present invention.

EXAMPLE 1 Two hundred grams (0.87 mole) of bis-ethylene pyrophosphate,prepared by the method of US. Pat. No. 3,159,591, and [46 grams (2.43moles} of urea were mixed and heated in an open vessel. Gas evolutionbegan at about C. A rapid increase in viscosity began at about C. Atabout C. a vigorous exothermic reaction began. with evolution of largevolumes of gas. The peak exotherm temperature was not observed but wasabove 240C. The resulting condensation product, after being cooled, wasa porous brittle solid material, slowly soluble in water, this solutionshowing a pH of 3-4.

Elemental analysis of the product was: carbon l9.9 percent; hydrogen,5.0 percent, phosphorus, 18.4 percent and nitrogen, l7.6 percent.

It has been found that the urea-bis-alkylene pyrophosphate condensationproducts employed in the present invention, are hydrolyzed in soil andultimately yield their entire nitrogen and phosphorus content to thesoil for use by growing plants.

Many crops, especially those with high nitrogen requirements,necessitate several applications of conventional nitrogen containingfertilizers over the course of the growing season. lt has now been foundthat fertilizers containing the urea-bisalkylene pyrophosphatecondensation products of the present invention can be applied to thesoil in a single application to supply a constant and uniform rate ofnitrogen and phosphorus release to the soil over a prolonged period oftime with out "burning" or other damage to the plants. These productsthus serve as a continuing source of nigrogenous and phosphorus plantfood over this period of time. The use of this fertilizer permits aconsiderable savings in labor, equipment and storage facilities.

The condensation products can be employed as a fertilizer by themselvesor as admixtures of more than one condensation product or in combinationwith rapidlyavailable nitrogenous fertilizers such as, for example,

urea, ammonium sulfate, potassium nitrate, ammonium nitrate, and thelike. The normal ratios of nitrogenphosphorus and potassium are achievedby such mix ture and the added readily available nutrients is advantersofwater. The jars were scaled and held at 70F. for a period of up to 34weeks. The air in each jar was changed each week beginning at the end ofthe first week. Each soil treatment was analyzed for the prestageous ingiving quick growth response. A typical fcr- 5 ence of ammonium andnitrate-nitrite nitrogen after intilizer composition will contain fromabout 5 to about cubation periods of 2, 5, 9, 26 and 34 weeks. The am-40 percent by weight of nitrogen values, about 5 to monium nitrogen wasrecovered from the soil by exabout 50 percent by weight of phosphorusvalues and tracting the soil with 500 milliliters of water followed fromabout 5 to about 50 percent by weight of potasby distilling the ammoniafrom the water, collecting it sium values, in boric acid and titratingwith hydrochloric acid in a Also, the present slow-release fertilizercomponents conventional manner. The nitrate-nitrite nitrogen was can beused in combination with other ingredients used recovered by treatingthe soil remaining from the above in turf and crop care These include.for example, indistillation step with 4 grams of Devardas alloy(copsecticides, weed-killers, fungicides and other like comper 50percent; aluminum 45 percent; and zinc 5 perponents commonly used incombination fertilizer and I5 cent), which converts the nitrate-nitritenitrogen to am pest control compositions. in general, the urea-bismoniumnitrogen, and 70 milliliters of a 30 percent soalkylene pyrophosphatecondensation product will dium hydroxide solution. The mixture isdistilled and comprise from about 25 to 100 percent, by weight, of theammonia which comes off is collected in boric acid the total weight ofthe fertiliz r compositio and titrated with hydrochloric acid as above,The per- EXAMPLE n cent nitrogen recovered from the soil is calculatedas follows: A study was conducted to determine the effectiveness of theureabis-alkylene pyrophosphat e condensanitrogen recovered from tionproduct as a slow-release nitrogen fertilizer. In this h treated ilstudy, ureabis-ethylene pyrophosphate condensation "covered nitrugenaddedm X product, prepared in Example I, was compared in its ammoniumnitrogen release properties over a prolonged period of time againstUramite, a commercially It was established that the unhydrolyzed polymerdid available urea-formaldehyde fertilizer product of Al n t i terferewith thi b e analyti l procedure, lied Chemical Company, in both asubstantially neutral Table II ho th r lt of thi t d expfessgd as soiland an acidic soil. The composition of the soils was p r ent of ammoniumand nitrate-nitrite nitrogen reas follows: covered from the soil.

TABLE II Uramitc EPU Uramite EPU Treated Soil Neutral Soil Acidic SoilN05 N0," N0; N0," Analysis NH, Total NH, Total NH+ Total NH, Total No,No, No; No;

2 wet-ks 46 4s 2l 20 41 2e 8 34 45 o 45 5 weeks 0 e3 63 i9 23 42 7 47 5457 u 57 9 weeks 0 e2 e2 9 29 38 3 65 68 3| 0 31 20 weeks 0 77 77 u as 680 84 84 45 43 s 34 weeks u 78 78 u 75 75 0 99 99 3(1 69 99 EPUhis-ethylene p ruphosphutc-urua condcnsalinn product NH, ammoniumnitrogen N().,+NO. nitrate-nitrite nitrogen Table 1 EXAMPLE IV In anadditional operation, 3 week old plots of rye P Organic Mechanic?Analyses grass were treated with an aqueous suspension of bis- MatterSand Silt Clay ethylene pyrophosphate-urea condensation product AcidSoil 5.7 1.5 59 35 6 applied as a spray at a rate equal to 8 pounds ofnitro- Neum" 73 24 3 gen per 1000 square feet. The plots were maintaineddetermined by wet-ash method i giwn in percent of total soil weightvunder Conditions Cunducive to good plant growth for determined byhydrometer method A given in percent of total soil weight three WfiekS.At Ihfi end Of this period, the plants Wf found to be in good growth andin good color indicative of nitrogen release from the fertilizer anduptake by the rye grass No phytotoxic symptoms were observed. To each ofseparate neutral and acidic soils as set forth hereinabove was added oneof Uramite or bis- EXAMPLE V ethylene pyrophosphate-ufea condensation dt as In an additional operation, separate pots of a soil havthe solefertilizer, i.e. nitrogen source, in an amount ng 3 Sand, Silt and yContent of i4 and 6 P calculated to add to the soil 200 parts ofnitrogen per respectively, a pH of 7.3 and an organic matter contentmillion parts of soil. The soil fertilizer mixtures were of 0.4 percent,were planted with corn at 4 seeds to a thoroughly blended on a rollermill. Fifty-gram aliquots of each composition were placed in 4-ouncejars; the neutral soil samples were moisturized with 10 milliliters ofwater and the acidic soils moisturized with 15 millilipot. One pot wasfertilized with a mixture of bisethylene pyrophosphate-urea condensationproduct, prepared as in Example I, and a potassium source and applied tothe soil as an in-row" application, in a nar' Table Ill TreatmentUnt'cnilized with EPU Check Color of Plant Green Yellow/Green AverageHeight 34.8 inches 319 inches Average Green Weight 68.6 grams 46.2 gramsAverage Dry Weight l5.0 grams 1 1.6 grams Average of II plants. 3replicates of 4 plants per pot.

Urea(l8 grams, 0.3 mole) was mixed with bisethylene pyrophosphate (23grams, 0.1 mole). The mixture was heated in an open vessel to 170C, atwhich point a vigorous exothermic reaction with evolution of gasoccured; the mixture became very viscous and subsequently solidified oncooling. Analysis showed carbon, 20.2 percent; hydrogen 4.4 percent;phosphorus, [7.1 percent and nitrogen, l9.6 percent. The hard, glossysolid was slowly soluble in water, in which is showed an apparentmolecular weight of I89.

Other urea-bis-alkylene pyrophosphate condensation products are preparedwherein the molar ratio of the urea to bis-alkylene pyrophosphate variesover the range of from lzl to 5:1 ureazbis-alkylene pyrophosphate. Theresulting condensation products, while not quite as homogeneous as thepreferred product, do, when used as slow release fertilizers, giveresults similar to that ofthe preferred 3: l condensation product.Similarly, products wherein the alkylene group is 1,2- or 1,3-propylene,1,2-, 2,3- or 13- butylene, l,2-, 2.3-, l,3-, 2,4- or 3,4- octylene,phenylethylene, l,-phenyl- 2,3-butylene and cyclohexylene are also foundto give similar results.

What is claimed is:

l. A method of fertilizing the soil which comprises applying to the soila bis-ethylene pyrophosphate-urea condensation product prepared by thecondensation of about 3 molecular equivalents of urea with about Imolecular equivalent of bis-ethylene pyrophosphate.

1. A METHOD OF FERTILIZING THE SOIL WHICH COMPRISES APPLYING TO THE SOILA BIS-ETHYLENE PYROPHOSPHATE-UREA CONDENSATION PRODUCT PREPARED BY THECONDENSATION OF ABOUT 3 MOLECULAR EQUIVALENTS OF UREA WITH ABOUT 1MOLECULAR EQUIVALENT OF BIS-ETHYLENE PYROPHOSPHATE.